Biocell - Biofuel containing mixtures of isomers of alkyl glucose or their hydrogenation product and its production process from cellulose or starch using as a solvent a mixture of an alkyl alcohol, an ionic liquid immiscible with water and hydrochloric acid

ABSTRACT

Biofuel containing mixtures of isomers of alkyl glucose in the linear form, pyran or furan forms, as well as their hydrogenation products. 
     Methyl cellulose may contain one to four methyl groups substituting hydrogen atoms in the original hydroxyl groups contained in glucose, the monomer of cellulose. 
     Its production process from cellulose or starch uses in the first step, as a solvent, a mixture of alkyl alcohol, an ionic liquid immiscible with water like trioctyl amine, tributylamine or their mixtures as hydrochlorides and hydrochloric acid. 
     In the second step, after the methanolysis of cellulose and the methylation of glucose catalysed by the acid, the methyl glucose molecules are separated by extraction with water. 
     Water is evaporated and the biofuel, alkyl cellulose, is obtained and identified by elemental analysis, NMR and FT-IR. 
     As an option, alkyl glucose is hydrogenated and converted in dimethyl tetrahydrofuran, which is a gasoline component.

1. FIELD OF INVENTION

Liquid biofuels from cellulose, ionic liquids, renewable energy, solvent extraction from ionic liquids

2. BACKGROUND OF THE INVENTION

The world production of cellulose on land is 40 billion ton per year and the stock of cellulose is 700 billion ton.

The world consumption of fossil fuels is 8 billion ton per year.

The food production in the world is 3 billion ton per year.

From these 3 numbers we conclude that to take out from food, materials to produce bio ethanol or vegetable oils for biodiesel would not solve the problem of substituting fossil fuels, and would cause hunger.

On the other side, there are large surfaces of arable land, which are not cultivated or which produce can only plants not suitable for food. In these surfaces, the production of cellulose from trees, sugar cane or bush is possible. On the other side, cellulose containing biomass is a side product of many food crops.

Sugar cane, has yields of 80-100 ton per hectar, In one ton of sugar cane there are about 80 kg of sugar, which may be converted to 50 kg of bioethanol. Besides sugar there are 250 kg of cellulose and hemicellulose, which is a much bigger quantity than sugar, which is not converted to liquid fuels. There are also about 80 kg lignin, which may become a useful energy source in the conversion of cellulose in liquid biofuels.

Cellulose, hemicellulose and starch have been studied in the past as possible sources of raw materials for liquid fuels and chemicals.

Wood itself is since thousands of years an energy source. Biomass is used today to produce electricity, but electricity represents only 10% of the consumption of fossil fuels. It is therefore important to find a process to convert cellulose in liquid fuels, suitable for energy supply to transportation and industry, which represent 90% of the consumption of fossil fuels.

The use of electricity for transportation is being made since a long time with electric trains, fork lifts and cars, but its economy for most transports and the electricity availability are not competing with biofuels from cellulose.

The substitution of fossil fuels is also important because of the carbon dioxide which they produce by burning. Although cellulose also produces carbon dioxide by burning, the same quantity of carbon dioxide was taken before out of the atmosphere by photosynthesis in plants to produce cellulose.

Although the carbon dioxide content on earth was up to 6000 ppm 100 million years ago, it decreased to 250 ppm in the nineteen century and increased again up to 380 ppm. These sharp increase in the last century is caused by burning fossil fuels and causes dramatic climate changes due to the greenhouse effect.

As a consequence, to convert cellulose into a liquid fuel is since decades a challenge for scientists, because the existing cars and trucks could drive with such a liquid biofuel without major changes in the motor.

The exhausting oil reserves and the political dependence on unstable countries producing oil is also a major problem today.

Producing electricity from nuclear or from renewable sources like wind, waves, rivers or photovoltaic, is used today, but represents only 20-30% of electricity production. The rest is produced from fossil fuels.

The substitution of liquid fuels by electricity for transports creates a major problem of storage and transportation of electricity, which is technically possible, but far more expensive than the cellulose biofuels (Biocell).

Because cellulose is renewable, abundant and not producing carbon dioxide by burning if photosynthesis is considered, there has been recent scientific work on following subjects (Bibliography 1 to 13):

-   -   dissolution of cellulose in ionic liquids instead of traditional         processes using water and organic solvents     -   hydrolysis of cellulose in ionic liquids     -   dehydration of fructose in ionic liquids to hydroxylmethyl         furfural     -   hydrogenation in organic solvents of hydroxymethyl furfural to         isomers of dimethyl tetrahydrofuran     -   isomerisation of glucose to fructose     -   In our previous work (PCT WO 2008 053284, PCT IB 2008 03313,         U.S. patent Ser. No. 12/356,643, U.S. patent Ser. No.         12/476,402) we found that the hydrolysis of cellulose to glucose         in N methyl imidazol chloride or N methyl imidazol hydrogeno         sulphate was always followed by dehydration of glucose and the         production of oligomers of glucose both by incomplete hydrolysis         of cellulose and by intermolecular dehydration of glucose.     -   In our previous work we also found that the extraction of the         hydrolysis and dehydration products of cellulose by organic         solvents is always unfavourable, due to the small partition         coefficients.     -   We also found that the reaction products which we extracted with         organic solvents from the ionic liquid phase normally did not         appear in a GC-MS because they decomposed at the entrance of the         equipment. We concluded that they were possibly too polar, and         therefore more soluble in the ionic liquid tested than in         organic solvents immiscible with the ionic liquid phase like         3-pentanone, diethyl ether, disopropylether, buthanol which we         tried.

2. DETAILED DESCRIPTION OF THE INVENTION

It is well known that there are ionic liquids which are immiscible with water. We tried first trioctyl amine hydrochloride, but found that cellulose has a poor solubility. We tried a mixture of trioctyl amine and tributyl amine hydrochloride and found a good solubility for cellulose ant at the same time we kept a good immiscibility with water of this ionic liquid. In order to avoid the formation of side products from the intermediate Hydroxymethyl furaldehyde, we added 2-20% an alkyl alcohol, but not too much in order to keep cellulose soluble in the reaction mixture at the reaction temperature.

In order to catalyse the alcoholysis of cellulose, we added 2-15% of hydrochloric acid 37%.

Curiously the reaction mixture could be heated up to 210° C. without carbonizing. This was due to the reaction with alkyl alcohol of the hydroxyl groups of glucose.

We also made the reaction starting from glucose and hydroxymethyl furaldehyde. In the 2 cases the same NMR, FT-IR spectrum was found as when starting from cellulose.

The final reaction mixture was cooled to room temperature and mixed with a dialkyl ether. No cellulose precipitated, therefore we concluded that all the cellulose reacted.

This mixture was extracted with 3 portions of water, and the water extracts were vaporized.

The mixture of the alkylether increases the partition coefficients in favour of the water phase.

After vaporizing the water we got a liquid with a weight about 1.5 times more than the original cellulose weight, due to the incorporation of methanol used in the experiment in the glucose molecules.

The final reaction product could be mixed with diesel oil in the proportion of 5-30% and tested positively as a diesel motor fuel.

We also found that as an option, the alkyl glucose can be hydrogenated by well known processes in order to produce dimethyl tetrahydrofuran, which is an excellent component for gasoline.

Example

In a round flask with reflux condenser were introduced:

Trioctyl amine 35.3 g (0.01 mole) Tributylamine 9.2 (0.05 moles) Hydrochloric acid 37% 22 ml = 25 g (0.25 mole)

The water phase was decanted out.

After decanting we added:

Methanol 9.6 g (0.30 mole) Hydrochloric acid 37%  10 ml Cellulose   2 g

This mixture was heated to 200-210° C. during 2 hours.

After cooling, we added

Diisopropylether  50 g Water 100 g

After shaking, the two phases were separated. A new quantity of water was added, shaken and decanted.

The water phases were evaporated so that no more liquid came out at a bath temperature of 90° C. and 0.1 bar vacuum.

The residue was checked by NMR, FT-IR and elemental analysis. It was found to be a mixture of methylated glucose.

BIBLIOGRAPHY

-   1. Jaroslaw Lewkowski, Synthesis, Chemistry and Applications of     5-Hydroxymethyl-furfural and its derivatives, Arkivoc, 2001, 17-54 -   2. Claude Moreau, Annie Finiels, Laurent Vanoye, Dehydration of     fructose and sucrose into 5-hydroxymethylfurfural in the presence of     1-H-3-methyl imidazolium chloride acting both as solvent and     catalyst, journal of Molecular Catalysis A, 2006, 165-169 -   3. Fred Shafizedh, Saccharification of lignocellulosic materials,     Pure and Appl. Chem., vol 55, No 4, pp 705-720, 1983 -   4. Khavinet Lourvanij and Gregory Rorrer, Reaction rates for the     partial dehydration of glucose to organic acids in solid-acid     molecular sieving catalyst powders J. Chem. Tech. Biotechnol., 1997,     69, 35-44 -   5. Yuri Roman Leshkov, Christopher Barrett, Zehn Y. Liu, James A.     Dumesic, Production of dimethylfuran for liquid fuels from biomass     derived carbohydrates, Nature, Vol 447, 21 Jun. 2007, 982 -   6. Acid in ionic liquid: an efficient system for hydrolysis of     lignincellulose, Changzhi Li et al. Green Chemistry, 17 Dec. 2007 -   7. Cataklytic conversion of cellulose into Sugar alcohols Atsushi     Fukuoka et al. Angewandte Chemie, 2006, 45, 5161-5163 -   8. Pyranone by pyrolysis of cellulose, Fred Shafizadeh, Pure &     Applied Chem, 1983, 55-4, 705-720 -   9. Dissolution of cellulose with ionic liquids and its application—a     minireview, Shengdong Zhu et al, Green Chemistry, 2006, 8, 325-327 -   10. WO 2008/053284 A1—Liquid biofuels containing dihydroxymethyl     furan, Pedro Correia, priority date 9 Mar. 2007. -   11. PCT IB 2008 03313, Liquid biofuels containing 2 methyl     tetrahydro pyran, Pedro Correia -   12. USP application 123566643—Liquid biofuels from cellulose, Pedro     Correia -   13. Simple chemical transformation of lignocellulosic biomass into     furan for fuel and chemicals, J. Am. Chem. Soc. 2009, 131, (5),     1979-1985, Joseph Binder, Ronald Raines 

1. A biofuel containing mixtures of isomers of alkyl glucose or their hydrogenation product dimethyl tetrahydrofuran and its production process from cellulose or starch using as a solvent a mixture of alkyl alcohol, an ionic liquid immiscible with water and hydrochloric acid, followed by an extraction with water, an evaporation and as an option an hydrogenation.
 2. In the product of claim 1 where the alkyl glucose contains a methyl, ethyl, propyl or buthyl group and the number of hydroxyls of glucose which react with the alkyl alcohol can be one to four.
 3. In the process of claim 1 where the ionic liquids are trialkyl amines hydrochlorides or their mixtures and where the alkyl groups contain 1 to 10 carbon atoms, preferably 4 and 8 in proportions of 1 of the tributylamine to 2 until 10 of the trioctyl amine.
 4. In the process of claim 1 where the alcohol mixed with the ionic liquid is an alkyl alcohol with a number of carbon atoms from 1 to 10, preferably one carbon atom and where the proportion of alcohol to ionic liquid may vary from 1% to 30%, which can be added at the start of the reaction or in small rates during the reaction.
 5. In the process of claim 1 where the amount of hydrochloric acid 37% added to the ionic liquid is 1% to 15%.
 6. In the process of claim 1 where the reaction time is 20 minutes to 180 minutes and the temperature 150 to 250° C.
 7. In the process of claim 1 where before extraction of the ionic liquid reaction phase with water, the ionic liquid reaction phase is mixed with a dialkyl ether to improve the partition coefficients and reduce viscosity, where preferably the ether is diethyl, diisopropyl or dibutyl ether or their mixtures.
 8. In the process of claim 1 where the water extracts are concentrated by evaporation.
 9. In the process of claim 1 where the alkyl glucose biofuel is added directly to diesel oil, or with the addition of an alkyl alcohol to make mixing easier, where the alcohol may contain 1 to 6 carbon atoms
 10. In the process of claim 1 where the alkyl glucose is hydrogenated by well known processes to dimethyl tetrahydrofuran, which is used as a gasoline component and not as a diesel component. 